When working on a roof, it is customary to employ a ladder to climb up and down from the ground, and one or more furthur ladders are usually laid directly on the roof, to climb up and down either side of the roof. Various simple expedients are used in order to attach the further ladders in position. In some cases ladders are used on either side of the roof, and are simply tied together at the ridge. In other cases, other forms of attachment may be used. In either case, they are generally somewhat crude on the spot expedients, and are more or less dangerous or at least unsatisfactory.
In addition, in almost all cases the ladder will simply lie directly on the roof. This may well damage the roofing material such as shingles.
In addition, as a workman climbs the ladder, the rungs of the ladder will only be spaced from the roof by about a distance of one inch or less. Thus as he puts his foot on the rung the toe of his boot is almost certain to damage the roof.
In addition, it means that the ladder is somewhat hazardous to use since the workman is only able to obtain a somewhat insecure toe hold on each rung.
For all of these reasons, it is therefore desireable to have a roofing ladder which is both easier to install and secure and is less likely to damage the roof, and in particular is safer to use.